lundi 9 janvier 2017, par Anne-Lise Maire (MPIA, Heidelberg, Germany)
Lundi 23 janvier 2017 à 16h00 , Lieu : Salle de conférence du bâtiment 17
The SAO 206462 (HD 135344B) disk is one of the few known transitional disks showing asymmetric features in both scattered light and thermal emission. Giant planets in formation have been suggested for accounting for the disk morphology. We obtained new high-contrast and high-resolution near-infrared images of the target with the VLT planet finder instrument SPHERE. The spiral arms and the outer rim of the inner cavity are revealed at high sensitivities without the need for image post-processing. We do not detect any close-in companion candidates. As for the derivation of the detection limits on putative giant planets embedded in the disk, we show that the knowledge of the disk aspect ratio and viscosity is critical for the estimation of the attenuation of a planet signal by the protoplanetary dust because of the gaps that these putative planets can open. Given the assumptions on these parameters, the mass limits can vary from 2-5 to 4-7 Jupiter masses at separations beyond the disk spiral arms. Our deep detection limits provide new constraints on a few recent predictions of massive planets in the outer disk based on the spiral density wave theory.
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